94 Roofs

In many cases the thermal performance of roof structures is similar to that of walls, and calculations can be performed in a similar way to that described in the previous examples. As was the case with walls, metal penetrations through the insulation will exact a penalty. With roofs these penetrations will usually take one of several forms. The first form is the installation of batt insulation between z-purlins, similar to that discussed in Section 9.3. The performance of these assemblies will be similar to that of similarly constructed walls.